ABSTltACTThe vegetation/soil relationships of six tall-tussock (ClJ(onocllloa) species are described for the high rainrall environment of the Murchison Mountains in Fiordland. Soil profile features. bulk densities, and chemical properties including inorganic phosphorus fractions are described for the soils at a range of sites. Field collections of the tall·tussock shoots were divided into three components and analysed for selected macro-c:lements.For shoot dry weight the species arc in the order: C. {lallesuns (3.77 8) Variability in concentration of elements within the !lhoot is similar for all !lix species: Ca and Mg arc consistently higher, Nand S usually higher, K and Na consistently lower, in the green blades than in the sheaths. All elements e)(ccpt Ca and Mg afe lowest in the dead tips of the shooots. Variability in element concentration between tussocks of the aame species at one !lite is: Na > K, Mg, Ca, S > P, N.Significant differenccs exist in element coneer.tration between sites and species. The highest concentrations of P, N, K, Mg, and Ca are in C. pallens in the alrine zone, on youthful soils with high levels of total inorJanic P and high proportions 0 Ca·bound • ." developed on talus coneS. Shoot concentrations of these elements arc lower, but Na is higher, where C. pallens grows on older soils. C. acicu/arls, C. ,erell/olla, and C. crassiuscu/a are associated with the most organic ~oil. which have low levels of inorganic P and Ca. bound-Po Here the shoots of these specIes have low P, N, K, Mg. and Ca concentrations but C. crass;uscu/a shoots have high Na and S concentrations. 'Concentrations and weights of elements per shoot are highc:r in C. cra.fSluscu/a where it grows with C. pal/ens. These results arc discussed in relation to the processes of vegetationl soilaystem development in the alpine zone.~w levels of all elements are found in C. r"bra Jrowing in wet alluvial loils in the subalpine lone. C. //allescens in the alpine lone is asSOCiated with soils having low levels o( Ca-bound-P, and a low concentration of Ca in the shoots. These results are discussed in relation to the present taxonomic: status of the species.

Results from rates of phosphate trials on potatoes grown on some recent and gley recent soils derived from greywacke alluvium were used to assess the ability of several methods of measuring available phosphorus to predict responses to phosphatic fertilisers.The relative yield of the control plots as a percentage of the maximum yield was used as the criteripn of response. Relative yields correlated well with the levels of aluminium-and calcium-bound phosphorus in those soils.The phosphorus extractants which were compared gave correlations with relative yields in the decreasing order: Bray No.2, Bray No.1, Olsen, Resin-exchange beads (24-hour), Truog, Resin exchange membrane, Egner-Riehm, Resin-exchange beads (two-hour).Since potatoes continue to absorb phosphorus during the whole of their growth period, a measure of the capacity of the soil to provide phosphorus throughout the growing season is required. The Bray No.2 method, especially when modified to five minutes extraction at a soil : solution ratio of 1 : 50, appears to fulfil this condition, more particularly because it extracts predominantly the aluminium-bound and the calciumbound soil phosphorus.

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AnSTI~ACTMacro-element concentrations of Chiol/ochloa rubra on volcanic soils are similar to previously reported concentrations in C. ruhra from high country yellow-brown earths in the South Island. Exceptions are Ca and N which are lower. and Mg which is very low and outside the range of South Island populations.Aluminium-bound P is the dominant fraction in young. weakly weathered volcanic soils beneath C. ruhru in the North Island. Bray No. I p. Olsen P. and green blade P concentrations decrea~e with altitude on MI. Ruapehu. and are closely positively correlated within North I sland-wide collections.

Inorganic phosphorus in three groups of South Island soils has been fractionated into aluminium-, iron-, and calcium-bound forms. Results show that Taitapu gley soils and Waimakariri recent soils in general contain the major part of their phosphorus in calcium-bound form; zonal soils contain a much lower proportion of this form. Highly significant relationships were found between the soil pH and the proportion of calcium-bound phosphorus for the Taitapu soils and for the zonal soils. This relationship approached significance for the Waimakariri soils, "Available" phosphorus was determined by five different methods. Correlation and multiple regression analyses indicated that the Truog extractant removed mainly calcium-bound phosphorus; the Bray No. 2 and Egner-Riehm extractants both aluminium-and calcium-bound phosphorus; the Bray No. 1 and Olsen extractants mainly aluminiumbound phosphorus. No extractant removed significant amounts of iron-bound phosphorus.